摘要
针对燃煤电厂选择性催化还原法脱硝期间产生的逃逸氨问题,本研究利用烟气中对氨气有吸收、吸附效果的水与飞灰建立降低氨逃逸及抑制粉尘排放的工艺,制造了可以增强吸收、吸附效果的微旋流模块。并通过实验室建立的以蒸汽发生器和模拟烟道为主要组成部分的模拟装置,分别在1.0、1.5、2.0 m/s这3种烟气流速下对该工艺的可行性及氨迁移特征进行了验证。同时,通过对气流进行改质,研究了影响除氨效率的因素,讨论了微旋流方法在脱硝工艺中对烟气除尘除氨的效果。研究结果表明,烟气流速、烟气湿度和飞灰是影响微旋流效果的主要因素。1.5 m/s为微旋流模块适合烟气流速,该流速下微旋流模块压降为20 Pa,除尘效率可达97.0%以上除氨效率可达到12.91%。烟气湿度越高,微旋流模块利用水吸收氨气降低气相氨含量的效率越高。飞灰会吸附氨气以降低逃逸氨,但当烟气潮湿时,飞灰表面的氨与铵盐会转化为氨气逸散入气相中,使逃逸氨增加。微旋流方法对脱硝烟气中表面附着氨与铵盐的飞灰有明显的去除效果,可降低飞灰板结对电除尘器和烟道的影响,可以方便的串联在脱硝工艺中以减少电除尘器工作负荷,降低电除尘器维护成本。
Aiming at the problem of ammonia escape during selective catalytic reduction denitration in coal-fired power plants,this study used water and fly ash in the flue gas that had absorption and adsorption effects on ammonia to establish a process to reduce ammonia escape and suppress dust emissions.A micro-swirl module that can enhance absorption and adsorption effects was manufactured.The feasibility and ammonia migration characteristics of the process were verified by the simulation device established in the laboratory with steam generator and simulated flue as the main components at three flue gas flow rates of 1.0 m/s,1.5 m/s and 2.0 m/s,respectively.At the same time,by modifying the airflow,the factors affecting the efficiency of ammonia removal were studied.The effect of micro-swirl method on flue gas dust removal and ammonia removal in denitrification process was discussed.The results show that the flue gas velocity,flue gas humidity and fly ash are the main factors affecting the micro swirl.The micro-swirl module is suitable for flue gas flow rate at 1.5 m/s.At this flow rate,the pressure drop of the micro-swirl module is 20 Pa.The dust removal efficiency can reach more than 97.0%.The higher the flue gas humidity,the higher the efficiency of the micro-swirl module using water to absorb ammonia to reduce the gas phase ammonia content.The fly ash will adsorb ammonia to reduce the escape ammonia.However,the ammonia and ammonium salt on the surface of the fly ash will be converted into ammonia gas and escape into the gas phase,increasing the escape ammonia when the flue gas is humid.The micro-swirl method has obvious removal effect on the fly ash with ammonia and ammonium salt attached to the surface of the denitration flue gas,which can reduce the influence of fly ash hardening on the electrostatic precipitator and flue.It can be easily connected in series in the denitration process to reduce the working load of the electrostatic precipitator and reduce the maintenance cost of the electrostatic precipitator.
作者
董月红
范培基
张书廷
刘涛
张泽
DONG Yuehong;FAN Peiji;ZHANG Shuting;LIU Tao;ZHANG Ze(China Energy Science and Technology Research Institute Co.,Ltd,State Key Laboratory of clean and efficient coal-fired power generation and pollutant control,Nanjing 210023,China;Tianjin University,Tianjin 300350,China)
出处
《电力科技与环保》
2023年第3期235-241,共7页
Electric Power Technology and Environmental Protection
基金
国家重点研发计划(2017YFC0210203)
国家重点实验室2020年开放课题基金支持项目(D2020Y004-15)。
关键词
微旋流
氨逃逸
烟气
飞灰
micro cyclone
ammonia escape
flue gas
fly ash
作者简介
第一作者:董月红(1981-),女,高级工程师,主要从事电力科技与环保的研究。E-mail:12067694@chnenergy.com.cn。
